268 
The March to Banza Nkulu . 
drift downwards. The aneroid now showed 860 
feet of absolute altitude, and about sixty-five feet 
above the landing-place of Banza Nokki ; the 
distance along the stream is fourteen miles, and 
thus the fall will be about five feet per mile below 
the Borongwa ya Vivi. We could see from a 
level the “ smaller rapids of Vivi” bursting through 
their black gate with angry foam, flashing white 
from side to side. No canoe could shoot this 
“ Cachoeira,” but I do not think that a Nile Da- 
habiyah or a Brazilian Ajojo would find great 
difficulty. Between us and the rapids, the con¬ 
cavity of the southern bank forms a bight or bay. 
The vortices, in which Tuckey’s sloop was whirled 
round despite oars and sails, and in whose 
hollow the punt entirely disappeared, “ so that 
the depression must have been three or four feet 
deep,” were nowhere seen at this fuller season. 
The aspect of the surface is that of every large 
deep stream with broken bottom ; the water boils 
up in ever widening domes, as though a system of 
fountains sprang from below. Each centre is ap¬ 
parently higher than its circle; it spreads as if a 
rock had been thrown into it, and the outer rim 
throws off little eddies and whirls no larger than a 
thimble. The mirrory surface of the lower river 
thus becomes mottled with light and shade, and 
the reflected image of the trough-cliff is broken 
into the most fantastic shapes. 
